Psychometric properties of the PROMIS short form measures in a U.S. cohort of 961 patients with chronic hepatitis C prescribed direct acting antiviral therapy

Background: To better understand symptoms experienced by patients infected with chronic hepatitis C virus (HCV), valid and reliable patient-reported outcome (PRO) measures are needed. Aim: To assess the reliability and validity of 10 patient-reported outcomes measurement information system (PROMIS) measures and the Headache Impact Test-6 (HIT-6) in a large national sample of patients with HCV. Methods: Pre-treatment data from 961 patients with HCV starting direct acting antiviral therapy at 11 U.S. liver centers were analyzed. Internal reliability was evaluated using Cronbach's alpha coefficient; frequency distributions were examined for floor and ceiling effects; structural validity was investigated via item-response-theory models; convergent validity was evaluated using correlations with theoretically-similar items from the HCV-PRO and memorial symptom assessment scale (MSAS); and known-groups validity was investigated by observing PRO differences by liver disease status and number of comorbidities. Results: The HIT-6 and the majority of the PROMIS measures yielded excellent reliability (alphas ≥ 0.87). Ceiling effects were infrequent (< 4%), while 30%-59% of patients reported no symptoms (floor effects). The data supported structural validity of the HIT-6 and most PROMIS measures. The PROMIS measures showed moderate to strong correlations with theoretically-similar items from the HCV-PRO and MSAS (0.39-0.77). Trends were observed between worse PRO scores and advanced cirrhosis and greater number of comorbidities, lending support for known-groups validity. Conclusions: The psychometric properties of the HIT-6 and PROMIS measures performed satisfactorily in this large cohort of patients with HCV starting direct acting antiviral therapy. Opportunities exist for further refinement of these PROs. Evaluation of performance over time and in under-represented subgroups is needed

Weaning Date for Spring Calving Cows Grazing Sandhills Range

A two-year experiment was conducted with March calving cows to determine the effect of the weaning date on cow body condition score, cow body weight, and calf body weight. Treatments were of eight weaning dates imposed at consecutive two-week intervals, beginning in mid-August and ending in late November. Cow body condition score declined linearly as weaning date was later in the fall. Calf body weight gains from August through November increased with weaning dates from August 18 through October 13; however, weaning after October 13 provided no advantage of increased calf body weight gain